Huldén, Lena, 2001. Terra 113, 171-8. Oak barrels and the medieval warm period in Satakunta [Finland] (Finnish) .
The English abstract states:
Historical sources regarding taxation suggest that there were large oak stands in medieval Satakunta in southwestern Finland. Oak stands about 150 km north of the current oak zone imply a warm period with 1-2 degrees centigrade higher temperature than today, lasting for hundreds of years. The establishment of the customary rent to the Crown has been dated in Satakunta to the period 1250-1300. It consisted of several different parcels, including oak barrels. By examining in which parts of Satakunta taxes were paid inoak barrels, it is possible to determine where oak grew during the periods 1250-1300 and 1540-1560. The peasants exploited oak stands as long as possible, but intensified land use and colder climate probably led to a rapid decline or vanishing of the oak in Satakunta as early as the end of the 16th century